Gear cutter



Patented May 27, 1924,

ALBERT A. GROSSARTH, 0F LA GRANGE, ILLINOIS, ASSIGNOR TO MIEHLE PRINTINGPRESS & MANUFACTURING COMPANY, 0F CHICAGO, ILLINOIS, A CORPORATIONOFILLINOIS.

GEAR CUTTER. l

Application filed .Tune 15, 1922.

To all whom t may concern:

Be it known that I, ALBERT A. GnossAR'rH, a citizen of the UnitedStates, residing at La Grange, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements in GearCutters, of which the following is a specification.

This invention relates to gear cutters.

In a form of gear cutter wherein the sides are so nearly parallel thatside clearance must be given the teeth in order to produce propercutting action and where the grinding for resharpening is done on thefront of the teeth, it will be appreciated that the thickness of suchcutter is gradually reduced as resharpening is repeated. Side clearanceis necessary, especially in cutting teeth of the epicycloidal formwherein the cutter and, accordingly, the adjacent sides of adjacentteeth are parallel at the pitch line. Under these circumstances it willbe seen that the life of the ordinary gear cutter, which requiresfrequent sharpening, is relatively short.

One object of my invention is to increase the life of such gear cutters.

Another object is to provid-e a simple, durable and eilicient gearcutter in which means is provided for compensating for the regrinding ofcutting teeth for sharpening the latter.

Another object is to provide a gear cutter which is capable of cuttingwith a uniform degree of accuracy regardless of the wearing of thecutting teeth as a result of regrinding same.

These and other objects are accom- .plished by means of the gear cuttershown on the accompanying sheet of drawings, in which-e Y Figure 1 is aside elevation of proved gear cutter; and

Figure 2 is a sectional view taken in the plane of line 2-2 of Figure 1.

The gear cutter comprises two annular members 10 and 11 havingcircumferentially spaced complementary tooth or cutting elements 12 and13, respectively. Each cutting element has a top cutting edge 14 and aside cutting edge 15. The upper surface 16 of each cutting elementnaturally recedes and the sides 17 of the. cooperating cutting elementconverge rearwardly to provide proper side clearance,this beingespecially neces sary in forming teeth of the epicycloidal my im- SerialNo. 568,462.

form wherein the side lcutting edges of the teeth are parallel at thepitch line. The two members 10 and 11 of the cutter,` as shown in Figure2, are spaced axially with respect to each other by means of anysuitable spacer 18, but it will be understood that when the cutter isnew no spacer'18 ywill be used. In other words, the two cutter members10 and 11 will have their adjacent surfaces in engagement with eachother. Spacers preferably are inserted only between the members 10 and11 to compensate for the decrease in width of the teeth occasioned byregrinding. It will be appreci ated that when the leading surface ofeach cutting element 12 and 13 is ground for sharpening the cuttingedges 14 and 15 the total width of the cutting' surface of the compositetooth will be decreased because of the side clearance. Accordingly, ifit is desired 'to maintain the cutting teeth of the gear cutter of thesame effective size it will be necessary to space said gear cuttermembers 10 and 11 from each other axially a variable amount, dependingupon the amount of grinding which has been done and the number of timessuch teeth are ground. Accordingly, to compensate for such grinding ofthe cutting teeth the spacer. 18 is interposed between the gear cutterelements 10 and 11, and it will be appreciated that the size of thespacer 18 is to be varied in accordance with the amount of grindingwhich has taken place. The adjacent inner edges of the cutting teeth atthe top thereof are provided with grooves 19 to prevent packing of chipsat such points.

In actual use the gear cutter members 10 and 11 are secured betweencollar members 2O and 21 having barrel portions 22 and 23 respectivelywith interengaged threaded portions for accommodating the cutterregardless of the width of same at the base thereof. As shown, the gearcutter members 10 and 11 are keyed' to one of the collar members 20 bymeans of a key 24, and the other collar member 21 is keyed to anysuitable support or arbor 25 by means of a key 26.

It is my intention to cover all modifications of the invention fallingwithin the spirit and sco-pe of the following claims.

I claim:

1. A gear cutter comprising a plurality of members having complementarycutting teeth with side clearance whereby when the front cutting edgesof such teeth are ground for sharpening same, the 'tota-l Width ot alcomplete tooth is lessened, said members being capable of being spaced avariable amount to compensate for such grinding, and a spacerinterposed@ between said teeth for controlling the effective total Widththereof.

2. A gear cut-ter comprising a plurality of members each havingcircumferentially spaced cutting teeth adjacent each other' axially, thesides of such teeth having side clearance whereby When the front cuttingedges of such teeth are gro-und for sharpening same, the total Width ofa complete tooth is lessened, said members being capable of being spaceda variable amount to compensate for such grinding, and a spacerinterposed between said teeth for controlling the effective total Widththereof.

3. A gear cuttercomprising a plurality of cutting elements which may bespaced apart a variable amount to compensate for grinding of suchcutting elements for resharpening saine, and a spacer interposed betweensaid cutting'elements Yfor controlling the ei:- iiective total Widththereof.

4;. A gear cutter vcomprising a plurality of cutting elements which maybe spaced apart a varia-ble amount to compensate for grinding` ot suchcutting` elements tor resharpening same, there being a groove on the topof. one of said cutting elements for preventing the packing of chips atsuch point.

Signed at. Chicago, llinois, this 2nd day of June, 1922.

ALBERT A. GROSSARTH.

